What is Big O. Big O is a form of Omaha poker where instead of four cards, players receive five cards. The format is also played Hi-Lo split with half the pot being awarded to the high hand, and the other half to the low hand - providing there is a low hand that qualifies under the 8 or Better rule.

Whether the cards are from the same suit or different suits is seen from the additions s - suited/same suit or o - offsuit/different.